The masking of antigens on trophoblast and cancer cells

From Autonomy to Integration, From Integration to Dynamically Balanced Integrated Co-existence: Non-aging as the Third Stage of Development

Reversible senescence at the cellular level emerged together with tissue specialization in Metazoans. However, this reversibility (ability to permanently rejuvenate) through recapitulation of early stages of development, was originally a part of ontogenesis, since the pressure of integrativeness was not dominant. The complication of specialization in phylogenesis narrowed this "freedom of maneuver", gradually "truncating" remorphogenesis to local epimorphosis and further up to the complete disappearance of remorphogenesis from the ontogenesis repertoire. This evolutionary trend transformed cellular senescence into organismal aging and any recapitulation of autonomy into carcinogenesis. The crown of specialization, Homo sapiens, completed this post-unicellular stage of development, while in the genome all the potential for the next stage of development, which can be called the stage of balanced coexistence of autonomous and integrative dominants within a single whole. Here, completing the substantiation of the new section of developmental biology, we propose to call it Developmental Biogerontology.

Aiming for the Sweet Spot: Glyco-Immune Checkpoints and γδ T Cells in Targeted Immunotherapy

Though a healthy immune system is capable of recognizing and eliminating emergent cancerous cells, an established tumor is adept at escaping immune surveillance. Altered and tumor-specific expression of immunosuppressive cell surface carbohydrates, also termed the “tumor glycocode,” is a prominent mechanism by which tumors can escape anti-tumor immunity. Given their persistent and homogeneous expression, tumor-associated glycans are promising targets to be exploited as biomarkers and therapeutic targets. However, the exploitation of these glycans has been a challenge due to their low immunogenicity, immunosuppressive properties, and the inefficient presentation of glycolipids in a conventional major histocompatibility complex (MHC)-restricted manner. Despite this, a subset of T-cells expressing the gamma and delta chains of the T-cell receptor (γδ T cells) exist with a capacity for MHC-unrestricted antigen recognition and potent inherent anti-tumor properties. In this review, we discuss the role of tumor-associated glycans in anti-tumor immunity, with an emphasis on the potential of γδ T cells to target the tumor glycocode. Understanding the many facets of this interaction holds the potential to unlock new ways to use both tumor-associated glycans and γδ T cells in novel therapeutic interventions.

From cancer to rejuvenation: incomplete regeneration as the missing link (part II: rejuvenation circle)

In the first part of our study, we substantiated that the embryonic reontogenesis and malignant growth (disintegrating growth) pathways are the same, but occur at different stages of ontogenesis, this mechanism is carried out in opposite directions. Cancer has been shown to be epigenetic-blocked redifferentiation and unfinished somatic embryogenesis. We formulated that only this approach of aging elimination has real prospects for a future that is fraught with cancer, as we will be able to convert this risk into a rejuvenation process through the continuous cycling of cell dedifferentiation-differentiation processes (permanent remorphogenesis). Here, we continue to develop the idea of looped ontogenesis and formulate the concept of the rejuvenation circle.

pH-Triggered geometrical shape switching of a cationic peptide nanoparticle for cellular uptake and drug delivery

The geometry of nanoparticles plays an important role in their performance as drug carriers. However, the pH-triggered geometrical shape switching of a cationic peptide consisting of isoleucine and lysine is seldom reported. In this work, we designed a cationic peptide with acid reactivity that can be loaded with the poorly soluble antitumor drug (doxorubicin (DOX)) to enhance tumor cell uptake and drug delivery. In a weakly acidic environment, a large portion of random coil structures formed, which subsequently led to nanoparticle destruction and rapid DOX release. In vitro studies demonstrated that this cationic peptide exhibits low toxicity to normal cells. The amount of DOX-encapsulating peptide nanoparticles taken up by tumor cells was greater than that taken up by normal cells. Our results indicated that the use of a weakly acidic microenvironment to induce geometric shape switching in drug-loaded peptide nanoparticles should be a promising strategy for antitumor drug delivery.

Epigenetic regulation of human placental function and pregnancy outcome: considerations for causal inference

Epigenetic mechanisms, often defined as regulating gene activity independently of underlying DNA sequence, are crucial for healthy development. The sum total of epigenetic marks within a cell or tissue (the epigenome) is sensitive to environmental influence, and disruption of the epigenome in utero has been associated with adverse pregnancy outcomes. Not surprisingly, given its multifaceted functions and important role in regulating pregnancy outcome, the placenta shows unique epigenetic features. Interestingly however, many of these are only otherwise seen in human malignancy (the pseudomalignant placental epigenome). Epigenetic variation in the placenta is now emerging as a candidate mediator of environmental influence on placental functioning and a key regulator of pregnancy outcome. However, replication of findings is generally lacking, most likely due to small sample sizes and a lack of standardization of analytical approaches. Defining DNA methylation "signatures" in the placenta associated with maternal and fetal outcomes offers tremendous potential to improve pregnancy outcomes, but care must be taken in interpretation of findings. Future placental epigenetic research would do well to address the issues present in epigenetic epidemiology more generally, including careful consideration of sample size, potentially confounding factors, issues of tissue heterogeneity, reverse causation, and the role of genetics in modulating epigenetic profile. The importance of animal or in vitro models in establishing a functional role of epigenetic variation identified in human beings, which is key to establishing causation, should not be underestimated.

Sialic Acid: its importance to platelet function in health and disease

Platelets are known to contain sialic acid, most of which resides on glycoprotein carbohydrate side-chains. A large proportion of the platelet sialic acid is neuraminidase-labile. The sialic acid of human platelets is of the N-acetyl neuramininic acid type and is implicated in platelet functional events, such as aggregation and adhesion as well as contributing to the platelet's electrophoretic mobility. In this respect the platelet has an overall electronegative charge which is predominately the result of the carboxyl group of the sialic acid moiety. Platelet subpopulations have been isolated with differing amounts of sialic acid and cleavage of platelet sialic acid by neuraminidase is associated with loss of platelets from the circulation. This has relevance to platelet aging in vivo where removal of platelet sialic acid may reveal 'senescence antigens' which could facilitate platelet 'uptake' by the reticuloendothelial system. The importance of platelet sialic acid status has been described in certain platelet disorders such as some thrombocytopenias as well as particular disease states including malignancies and atherosclerosis.

Specific tumour-associated methylation in normal human term placenta and first-trimester cytotrophoblasts

Human placentation displays many similarities with tumourigenesis, including rapid cell division, migration and invasion, overlapping gene expression profiles and escape from immune detection. Recent data have identified promoter methylation in the Ras association factor and adenomatous polyposis coli tumour suppressor genes as part of this process. However, the extent of tumour-associated methylation in the placenta remains unclear. Using whole genome methylation data as a starting point, we have examined this phenomenon in placental tissue. We found no evidence for methylation of the majority of common tumour suppressor genes in term placentas, but identified methylation in several genes previously described in some human tumours. Notably, promoter methylation of four independent negative regulators of Wnt signalling has now been identified in human placental tissue and purified trophoblasts. Methylation is present in baboon, but not in mouse placentas. This supports a role for elevated Wnt signalling in primate trophoblast invasiveness and placentation. Examination of invasive choriocarcinoma cell lines revealed altered methylation patterns consistent with a role of methylation change in gestational trophoblastic disease. This distinct pattern of tumour-associated methylation implicates a coordinated series of epigenetic silencing events, similar to those associated with some tumours, in the distinct features of normal human placental invasion and function.

Pregnancy outcome and placenta pathology in Plasmodium berghei ANKA infected mice reproduce the pathogenesis of severe malaria in pregnant women

Pregnancy-associated malaria (PAM) is expressed in a range of clinical complications that include increased disease severity in pregnant women, decreased fetal viability, intra-uterine growth retardation, low birth weight and infant mortality. The physiopathology of malaria in pregnancy is difficult to scrutinize and attempts were made in the past to use animal models for pregnancy malaria studies. Here, we describe a comprehensive mouse experimental model that recapitulates many of the pathological and clinical features typical of human severe malaria in pregnancy. We used P. berghei ANKA-GFP infection during pregnancy to evoke a prominent inflammatory response in the placenta that entails CD11b mononuclear infiltration, up-regulation of MIP-1 alpha chemokine and is associated with marked reduction of placental vascular spaces. Placenta pathology was associated with decreased fetal viability, intra-uterine growth retardation, gross post-natal growth impairment and increased disease severity in pregnant females. Moreover, we provide evidence that CSA and HA, known to mediate P. falciparum adhesion to human placenta, are also involved in mouse placental malaria infection. We propose that reduction of maternal blood flow in the placenta is a key pathogenic factor in murine pregnancy malaria and we hypothesize that exacerbated innate inflammatory responses to Plasmodium infected red blood cells trigger severe placenta pathology. This experimental model provides an opportunity to identify cell and molecular components of severe PAM pathogenesis and to investigate the inflammatory response that leads to the observed fetal and placental blood circulation abnormalities.

Differential gene expression profile reveals deregulation of pregnancy specific beta1 glycoprotein 9 early during colorectal carcinogenesis

Background

APC (Adenomatous polyposis coli) plays an important role in the pathogenesis of both familial and sporadic colorectal cancer. Patients carrying germline APC mutations develop multiple colonic adenomas at younger age and higher frequency than non-carrier cases which indicates that silencing of one APC allele may be sufficient to initiate the transformation process.

Methods

To elucidate the biological dysregulation underlying adenoma formation we examined global gene expression profiles of adenomas and corresponding normal mucosa from an FAP patient. Differential expression of the most significant gene identified in this study was further validated by mRNA in situ hybridization, reverse transcriptase PCR and Northern blotting in different sets of adenomas, tumours and cancer cell lines.

Results

Eighty four genes were differentially expressed between all adenomas and corresponding normal mucosa, while only seven genes showed differential expression within the adenomas. The first group included pregnancy specific β-1 glycoprotein 9 (PSG9) (p < 0.006). PSG9 is a member of the carcinoembryonic antigen (CEA)/PSG family and is produced at high levels during pregnancy, mainly by syncytiotrophoblasts. Further analysis of sporadic and familial colorectal cancer confirmed that PSG9 is ectopically upregulated in vivo by cancer cells. In total, deregulation of PSG9 mRNA was detected in 78% (14/18) of FAP adenomas and 75% (45/60) of sporadic colorectal cancer cases tested.

Conclusion

Detection of PSG9 expression in adenomas, and at higher levels in FAP cases, indicates that germline APC mutations and defects in Wnt signalling modulate PSG9 expression. Since PSG9 is not found in the non-pregnant adult except in association with cancer, and it appears to be an early molecular event associated with colorectal cancer monitoring of its expression may be useful as a biomarker for the early detection of this disease.

Characterization of proteoglycans of human placenta and identification of unique chondroitin sulfate proteoglycans of the intervillous spaces that mediate the adherence of Plasmodium falciparum-infected erythrocytes to the placenta

In pregnant women infected with Plasmodium falciparum, the infected red blood cells (IRBCs) selectively accumulate in the intervillous spaces of placenta, leading to poor fetal outcome and severe health complications in the mother. Although chondroitin 4-sulfate is known to mediate IRBC adherence to placenta, the natural receptor has not been identified. In the present study, the chondroitin sulfate proteoglycans (CSPGs) of human placenta were purified and structurally characterized, and adherence of IRBCs to these CSPGs investigated. The data indicate that the placenta contains three distinct types of CSPGs: significant quantities of uniquely low sulfated, extracellular CSPGs localized in the intervillous spaces, minor amounts of two cell-associated CSPGs, and major amounts of dermatan sulfate-like CSPGs of the fibrous tissue. Of the various CSPGs isolated from the placenta, the low sulfated CSPGs of the intervillous spaces most efficiently bind IRBCs. Based on IRBC adherence capacities and localization patterns of various CSPGs, we conclude that the CSPGs of the intervillous spaces are the receptors for placental IRBC adherence. The identification and characterization of these CSPGs provide a valuable tool for understanding the precise molecular interactions involved in placental IRBC adherence and for the development of therapeutic strategies for maternal malaria. In the accompanying paper (Alkhalil, A., Achur, R. N., Valiyaveettil, M., Ockenhouse, C. F., and Gowda, D. C. (2000) J. Biol. Chem. 275, 40357-40364), we report the structural requirements for the IRBC adherence.

The fibrinoids of the human placenta: origin, composition and functional relevance

Placental fibrinoids are extracellularly deposited materials which are histologically glossy and acid staining, and can be found in every normal and pathological placenta at all stages of pregnancy. The amount of fibrinoid is, in general, independent of pregnancy outcome and fetal wellbeing. According to new findings, the classical histological term "fibrinoid" covers two distinctive extracellular matrices which differ as regards structure, composition and function. Fibrin-type fibrinoid is mostly composed of fibrin together with other molecules derived from blood clotting or degenerative processes. It is mainly a maternal blood-clot product which is used (a) to adapt the intervillous space to optimized flow conditions and (b) to control growth of the villous trees by encasing new villous branches which caused intervillous stasis or turbulence of maternal blood. Moreover, fibrin-type fibrinoid replaces degenerative syncytiotrophoblast at the maternofetal exchange surfaces, thus acting as a kind of substitute barrier. Matrix-type fibrinoid is a secretory product of invasive extravillous trophoblast cells. It shares some similarities with basement membranes, however, it is secreted in an apolar fashion, embedding the secreting cells. Like basement membranes, it contains laminins, collagen IV, and heparan sulfate. In addition, oncofetal fibronectins, vitronectin, and i-glycosylated molecules but no collagens I, III, and VII can be found. Matrix-type fibrinoid is thought to regulate trophoblast invasion by specific interactions with cell surface integrins. As a kind of "glue", it anchors the placenta to the uterine wall and seems to play an important role in materno-fetal immune interactions at this particular site. Both types of fibrinoid are usually co-localized, thus indicating close morphogenetic and functional interrelations.

Distribution of proteoglycans during the hair growth cycle in human skin

The involvement of proteoglycans in hair growth has been recognized through the observation of increased hair growth in diseases such as the mucopolysaccharidoses and pre-tibial myxedema, which involve an increase in skin proteoglycan content. In an attempt to understand this, we have examined the distribution of chondroitin 6 sulphate (C6S), unsulphated chondroitin (COS), dermatan sulphate (DS), and heparan sulphate proteoglycans (HSPG) in frozen tissue sections of normal scalp by immunostaining. Results show that during anagen, the thick connective tissue sheath around the follicle strains strongly for C6S, COS, and DS. COS is uniquely associated with this region and is not found beneath the epidermis or infundibular epithelium. HSPG is, however, localized in the basement membrane zone adjacent to the outer root sheath. In addition, all of these proteoglycans are localized in the dermal papilla. In mid-catagen, we observed significant loss of C6S and COS staining from both the dermal papilla and the connective tissue sheath, but no decrease in staining for HSPG. In late catagen, very little staining of C6S and COS was observed. In early anagen, we observed that C6S was again present in the connective tissue sheath and dermal papilla; however, COS staining appeared to be weaker and less closely associated with the follicle. HSPG staining was observed in early anagen in a pattern very similar to that found for other basement membrane components. Results for DS were not obtained for catagen or early anagen. These results provide further evidence that hair growth is associated with the presence of chondroitin proteoglycans in the follicle environment and that the cessation of growth is associated with their removal. Further studies are underway to characterize the relationship between hair growth and proteoglycans.

Monoclonal antibodies to the human mammary gland: III. Monoclonal antibody LICR-LON-M18 identifies impaired expression and excess sialylation of the I(Ma) cell-surface antigen by primary breast carcinoma cells

Monoclonal antibody LICR -LON- M18 identifies the immunodominant oligosaccharide sequence of the I(Ma) blood-group antigen: Gal beta 1----4GlcNAc beta 1----6--. In primary breast cancers this structure is almost totally cryptic, due to "masking" by sialic acid, but can be revealed by digestion with the specific glycosidase neuraminidase. Following desialylation, light microscopic immunohistochemical examination has revealed the epitope identified by LICR -LON- M18 to be heterogeneously distributed throughout the population of breast carcinoma cells. These tumor cells express the antigen as both a cytoplasmic and a surface membrane determinant. In the normal human breast, this structure is expressed exclusively along the luminal plasma membranes of the duct and alveolar littoral epithelial cells. Desialylation of tissue sections of normal resting and lactating breast epithelium with neuraminidase virtually abolishes the heterogeneous intercellular distribution of the I(Ma) determinant. In desialylated nonneoplastic breast tissues, the expression of this antigen is observed within the cytoplasm of some myoepithelial cells, but not in the littoral epithelial cells. The expression of the I(Ma) antigen by neoplastic and normal breast epithelial cells has also been compared with that of the oligosaccharide sequence Gal beta 1----3GalNAc. This structure, recognized by peanut agglutinin, forms the dominant portion of the Thomsen-Friedenreich antigen. With respect to normal and lactating breast epithelial cells, both oligosaccharide structures are sialylated and appear to be similarly misprocessed by breast carcinomas. The masking of surface carbohydrate determinants and the faulty processing of structures usually expressed on the surface of non-neoplastic breast epithelial cells may be important phenomena in the pathobiology of breast carcinomas.

Mucous metaplasia of epithelial cells in fibrocystic disease of the breast. A histochemical study

Mucous metaplasia of breast epithelium was studied by histochemical procedures in cases of fibrocystic disease. Epithelial mucins consist almost entirely of non-sulfated sialomucins. A slight amount of sulfated sialomucins was identified occasionally while neutral mucins seems to be absent. Abundant glycogen granules are contained in the cytoplasm of metaplastic cells. The secretion of sialomucins may be associated with a loss of cell antigenicity. In this case, the survival of metaplastic epithelium supports the hypothesis of the possible immunological nature of the disease.

Impairment of the thymus-dependent humoral immune response by syngeneic or allogeneic pregnancy

Pregnancy results in a diminished capacity of the gravid mouse to respond to thymus-dependent antigens. The IgM response to thymus dependent and independent antigens is relatively unaltered whereas the IgG response to thymus-dependent antigens is markedly suppressed in both syngeneic and allogeneic pregnancy. The impairment of the humoral immune response is not due to loss of antibody-forming precursor lymphocytes (AFPL) from the spleen since their number remains unaltered. During pregnancy the spleen becomes enlarged and the precursor frequency is diluted somewhat but the AFPLs retain their normal activity in vitro. This implies an alteration in their amplification by accessory cells (T cells or macrophages) is responsible for the impaired IgG responses.

A quantitative assay for the measurement of immune responses directed against the human placenta

A quantitative in vitro immune assay based on the classical chromium release assay has been developed to detect immune responses directed against alien antigens expressed by the developing foetus and present on the maternal-facing surface of the human placenta. A plasma membrane fraction from the surface of the placenta was prepared and the vesicles thus formed were radiolabelled with 51 Cr. The 51Cr-labelled vesicles, by various criteria, were found to be suitable for use as targets in a 'release assay'. Further, by means of experimentally immunised animals, the target membranes were shown to be capable of detecting both cellular and humoral anti-placental activity.

Carcinomas induced by cell lines cultivated from normal mouse placentas

Cell lines have been established from placentas of various strains of mice by in vitro cultivation. The established lines appear to be trophoblast cells as judged from their production of gonadotropin-like substance and their production of gonadotropin-like substance and steroid hormones. The cell lines lack detectable H-2 antigen, Fc receptor sites, Thy 1 and antigen and surface immunoglobulin determinants. In addition, the cells are resistant to murine type-C RNA tumor virus infection. The resistance is due to a block of viral replication after the stages of viral adsorption and penetration. The cell lines induced carcinomas after injection into adult mice of original host strains. Usually at least 2 x 10(6) cells are required to induce tumors by i.p. or s.c. injection. Transplantation of the tumor cells to various strains of mice revealed that some strains accepted and some strains rejected the transplant. Genetic crossings between susceptible and resistant mouse strains indicate that susceptibility to transplantation of tumor is determined by a single pair of dominant autosomal genes.

Review article: trophoblast invasion and the establishment of haemochorial placentation in man and laboratory animals

Trophoblast invasion is an essential component of haemochorial placentation and has to be considered to relation to reactive changes in the maternal uterine tissues. Some comparative aspects of human and laboratory rodents are discussed and, although there is an obvious phylogenetic gap between the two, many characteristics of placental development are found to be analogous. Trophoblast growth into the uterus is different in different species: localized trophoblast growth forming a bulky tissue (mouse, rat, hamster) contrast with a dispersion of independent trophoblastic elements, forming an interstitial invasion (guinea pig, man). In the rat, mouse, hamster and man retrograde intra-arterial trophoblast migration occurs in maternal vessels supplying blood to the developing placenta. Early changes in maternal tissue might influence trophoblast behaviour. Decidualization probably is a key phenomenon, and the relation of decidual necrosis to trophoblast invasion is considered. Some kind of controlled immune response by the mother also may be involved. These considerations apply to stromal or interstitial invasion as well as to intravascular trophoblast migration but, for the latter, haemodynamic factors probably influence tissue reactions.

Retrospective histochemical study of mucosubstances in adenocarcinomas of the gastrointestinal tract

Use of the PATS/KOH/PAS and PB/KOH/PAS techniques and the diamine method (Spicer 1965) together with the demonstration of metachromasia with toluidine blue pH 3.0, for the study of carbohydrates in a retrospective study of gastric and colorectal adenocarcinomas, disclosed an increase in the sulphate content and the absence of O-acylated sialomucins in the majority of gastric adenocarcinomas. In the colorectal tumours there is no change in the degree of sulphation normally present in this area, but the degree of acylation of the sialic acid in adenocarcinoma is very different to that of normal mucosa and appears related to the degree of differentiation of the tumour. The mucosa adjacent to tumours from both areas were also studied, as well as gastric intestinal metaplasia.

Immunological parameters in gestational trophoblastic neoplasia

Immunological function were studied in 22 patients with hydatidiform mole and 29 patients with malignant trophoblastic disease before and after treatment; normal pregnant and post-pregnant women served as controls. The only significant abnormality in hydatidiform mole was a low granulocyte chemotaxis before evacuation. In malignant trophoblastic disease the total lymphocyte counts, T-cell counts. B-cell counts, lymphocyte responses to mitogens and serum IgA levels were significantly lower than in normal women 6 wk after pregnancy. In those who responded to chemotherapy, these indices rose to the levels of post-pregnancy controls. An 'immune profile score' based on these indices was found to be a useful prognostic index. All patients with hydatidiform mole who had a score of 7 or less developed malignant trophoblastic disease, while the two patients with malignant trophoblastic disease who died had the lowest scores of the series.

Trophoblast transferrin and transferrin receptors in the host--parasite relationship of human pregnancy

Transferrin and specific transferrin receptors are demonstrated on the microvillous surface of syncytiotrophoblast in human immature and term placentae by immuno histological techniques with the use of light and electron microscopy. That the distribution of transferrin is limited to the materno-foetal interface supports the hypothesis that binding of maternal transferrin to trophoblast receptors is involved in the process of iron transport to the foetus. Parallel studies with baboon placentae demonstrate the presence of trophoblast receptors which bind both baboon and human transferrin, thereby putting forward an experimental model which might be used to test the biological significance of placental transferrin receptors in primates. In addition, investigation of a large number of human cell lines shows that many transformed cells, but no normal cells (such as blood lymphocytes) or cells from primary culture (such as neonatal foreskin fibroblasts), possess the ability to bind transferrin to their membranes. These findings suggest that transferrin receptors may play important biological roles in addition to that of iron transport from mother to foetus. One such role could be the limitation of iron in intervillous spaces, thus depriving iron-requiring microorganisms of iron, hence serving as a non-specific factor of resistance for placentae. Another role for foetal transferrin receptors on trophoblasts could be to bind maternal transferrin at the materno-foetal interface, thus frustrating maternal immunosurveillance. This is similar to a mechahism used by schistosomes in the host-parasite relation where host proteins are bound by the parasite to escape immunological recognition. The presence of transferrin receptors on transformed cells suggests that this mechanism might also be employed by tumour cells. Finally, in view of previous studies which show that transferrin is required by stimulated lymphocytes to pass from the G1 to the S phase of cellular replication, it is proposed that trophoblast transferrin receptors could limit the amount of transferrin in intervillous spaces and thus impede the proliferation and possible cytotoxicity of maternal activated lymphocytes at the materno-foetal interface.

Serological studies of seromucoids from normal subjects and patients with malignant and non-malignant diseases

During investigations of serum from patients with carcinoma, elevated levels of two proteins were observed. The larger (MW approximately 44,000) was identified as (alpha-acid glycoprotein. The smaller MW approximately 20,000) has not yet been identified. Further investigation of alpha-acid-glycoprotein-containing seromucoid showed that many red blood cell and tissue antigens were present, for example, I, i, P1, Tja (P+P+Pk), H, A, B, Lea, Leb1, M and N. Differences in antigen content between normal serum and serum from carcinoma patients could be demonstrated quantitatively and qualitatively. Seromucoid preparations from patients with Hodgkin's lymphoma inhibited phytohaemagglutinin-induced lymphocyte transformation more often than seromucoid preparations from normal subjects.

Detection of sensitized human blood lymphocytes by agglutination with basic peptides: a possible test for malignant disease

A simple rapid micro-agglutination test for detecting sensitized lymphocytes from human peripheral blood is described: the poly-L-lysine (PLL) 3400 agglutination test of lymphocytes (PAL test). The incubation of lymphocytes from 30 cancer patients, 30 patients with non-malignant disease and 40 healthy controls with PLL (mol. wt 3400) is evaluated. The test was positive in 83 percent of malignant and 20 percent of non-malignant cases. All healthy controls were negative. Other peptides tested showed no significant difference in reaction between malignant and non-malignant diseases. The mechanism of detection of sensitized lymphocytes from patients with malignant disease through agglutination induced by PLL 3400 is discussed.

The immunosuppressive role of alpha-fetoprotein during pregnancy

Cell-mediated and humoral immune responses were assessed in mice at mid-term (day 10) in pregnancy. A significant but selective suppression of the primary in vivo antibody (plaque-forming cell) response to SRBC was observed, with the most pronounced effect being on the gammaA response. Similar results were obtained for secondary in vitro antibody synthesis by antigen-primed spleen cells from pregnant mice, demonstrating the intrinsic nature of the inhibition. Pregnant mouse serum (PMS) was shown to suppress primary in vitro antibody synthesis, and the inhibitory effect was abrogated by the selective removal of alpha-fetoprotein (AFP) using affinity chromatography. Normal mouse serum became similarly suppressive in vitro when purified AFP of fetal origin was added to it in concentrations approximating that found in PMS. Spleen cells from pregnant mice showed a suppressed mitogenic response to phytohemagglutinin, a lowered response to concanavalin. A, and a normal response to lipopolysaccharide. In contrast, the allogeneic response of these animals as measured in the one-way mixed lymphocyte culture was enhanced. PMS suppressed both allogeneic and mitogen-induced lymphocyte transformation by spleen cells from nonpregnant mice, and the effect was eliminated by the selective removal of AFP. These findings indicate an important functional role for AFP in normal embryological development.

Mucin histochemistry of human cholangiocarcinoma

Histochemical studies of mucins were carried out on 17 autopsy specimens of cholangiocarcinomas associated with clonorchiasis. All tumours produced epithelial mucins which were mixtures of neutral and acid mucopolysaccharides without any histochemically demonstrable components of sialic and uronic acids. The mucins were qualitatively similar to that secreted by normal and Clonorchis-infested bile ducts. However carboxymucins were reduced and sulphomucins were absent or present only in trace amounts in the neoplastic epithelium; in the hyperplastic epithelium in clonorchiasis sulphomucins were abundant. The HID-AB technique for sulphomucins is valuable in differentiating hyperplastic bile ducts and cholangiocarcinoma.

The nonuniform distribution of acidic components on the human placental syncytial trophoblast surface membrane: a cytochemical and analytical study

The surface coat of syncytial trophoblast from term human placentas was studied using cytochemical methods (colloidal iron, alcian blue-lanthanum nitrate, dialyzed iron) in coordination with tissue enzyme digestions (trypsin, neuraminidase) and sialic acid analyses. The presence of at least two highly acidic anionic components that contribute significantly to the surface negativity of trophoblast has been demonstrated. The first of these, sialic acid, was removed with neuraminidase. Tissue digestion with this glycosidase was accompanied by a decrease in trophoblast surface staining with colloidal iron, a decrease in tissue sialic acid, and an increase in the concentration of sialic acid in the incubating medium. Results from methylation experiments were consistent with the presence of sialic acid. The second anionic component(s) was identified by removal with trypsin of a glycocalyx constituent that stained with both colloidal iron and lanthanum. After trypsinization, tissue sialic acid levels were not significantly different from control values, and no detectable sialic acid was present in the incubating medium. The identity of this anionic component has not been established. Both sialic acid and nonsialic acid acidic components are distributed in higher density on membrane of microvilli than on intermicrovillous surface membrane. In addition, the sialic acid moieties appear to be clustered in the glycocalyx.

Depression of blast transformation of peripheral leukocytes by plasma from pregnant women

The blast transformation of peripheral leukocytes from pregnant and nonpregnant women has been studied at different time intervals with graded concentrations of phytohemagglutinin. The transformation is markedly depressed during pregnancy. Leukocytes from nonpregnant women and men show diminished transformation when cultured in a medium containing plasma from pregnant women.